1. Field of the Invention
The present invention relates to a drive system, and more particularly, to a propulsion system for a bicycle, or the like, having a vertically oriented, rectilinear motion path, wherein the rectilinear motion is converted to a rotary motion.
2. Description of Related Art
Humankind has long aspired to achieve a more physically fit body. Devices of all sizes, shapes and configurations have been created with this purpose in mind; exercises designed to develop specific muscles in particular ways have been designed by scientists, doctors, engineers and the weekend athlete. Some of these machines and techniques improve strength, some improve conditioning and others improve muscular tone.
Regardless of this multitude of mechanisms and techniques, many deficiencies yet exist with many physical conditioning devices. Such deficiencies include non-efficient application of muscle strength from the human body to the object of the exercise as well as lost power transference. Bicycles illustrate a class of widely used exercise machines which have been the subject of various refinements. Athletes often employ bicycles for exercise as well as competition. Bicycles are also used in many countries as a mode of transportation, in addition to a means of exercise. While bicycle manufacturers have sought to produce lighter bicycles, more flexible bicycles and more durable bicycles through the use of a variety of materials, the conventional bicycle continues to employ a less than completely efficient drive train. Although this area has received considerable attention in recent years a more efficient exercise and transportation apparatus yet remains to be developed.
Conventional bicycles incorporate an axle located approximately midway between the front and rear tires. Perpendicularly affixed to the axle are shafts, at the end of which are pedals that project outwardly from the bicycle. The pedals allow the user to utilize the propulsive power generated by the human body. The axle usually has a sprocket that engages a chain driving the rear tire, and which propels the bicycle forward. Thus, the axle, shaft, pedal configuration of the bicycle drive mechanism to force the rider to drive his or her feet and legs in a generally circular motion. This motion while effective in creating sufficient force to propel the bicycle forward, does not do so with maximum efficiency.
The rotational motion forced upon a rider by the drive mechanism of a conventional bicycle results in lost motion and wasted energy. The bicycle's drive is developed from the downward push of the rider's legs and feet along the circular path of the pedals, and the circular path makes it difficult for the rider to exert a constant propulsive force. This inherent lost motion problem decreases the rider's ability to pace himself or herself during a long journey. Thus, a drive system which eliminates lost motion and increases the length of the power stroke would be a marked advance over the prior art. The present invention accomplishes this goal, while increasing power uniformity and decreasing the length of the rider's reset stroke. In addition, the improved drive system results in a more efficient means for the application of propulsive power and for increasing the endurance of the rider.